Convergence of strong shock waves (SSW) in water results in formation of a warm dense state of water in the origin of implosion. Extreme parameters of water in the vicinity of the implosion, founded by 1D hydrodynamic (HD) numerical simulations coupled with equation of state of water and assuming symmetry of the SSW convergence, impose significant limitations on the applicable methods of diagnostics. In the present research we applied time- and space resolved spectroscopic measurements of light emission from water-plasma formed in the vicinity of the SSW implosion. The obtained emission spectrum in visible range was compared with the results of the radiative-transfer simulations in order to estimate the temperature assuming black body radiation. The time delay between the beginning of the SSW generation and light emission was used as the time of flight (TOF) of the SSW and compared with the HD simulation to estimate the pressure at that location. In experiments, the SSW was generated by underwater electrical explosion of a spherical wire array with different diameters and different materials of wires using microsecond timescale high-current pulse generator with stored energy up to 4 kJ. The results of this research showed that the obtained TOF of the SSW and emission spectra agree well with the results of the simulation showing that the water density, temperature and pressure should be larger than ~3 g/cm-3, ~1.4 eV and ~2×1011 Pa, respectively, at radii <25 µm with respect to the origin of the SSW implosion.